Information on EC 2.1.1.63 - methylated-DNA-[protein]-cysteine S-methyltransferase

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The expected taxonomic range for this enzyme is: Bacteria, Archaea, Eukaryota

EC NUMBER
COMMENTARY
2.1.1.63
-
RECOMMENDED NAME
GeneOntology No.
methylated-DNA-[protein]-cysteine S-methyltransferase
REACTION
REACTION DIAGRAM
COMMENTARY
ORGANISM
UNIPROT
LITERATURE
DNA (containing 6-O-methylguanine) + protein L-cysteine = DNA (without 6-O-methylguanine) + protein S-methyl-L-cysteine
show the reaction diagram
-
-
-
-
REACTION TYPE
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
methyl group transfer
-
-
-
-
methyl group transfer
-
-
methyl group transfer
-
-
SYSTEMATIC NAME
IUBMB Comments
DNA-6-O-methylguanine:[protein]-L-cysteine S-methyltransferase
This protein is involved in the repair of alkylated DNA. It acts only on the alkylated DNA (cf. EC 3.2.2.20, DNA-3-methyladenine glycosidase I and EC 3.2.2.21, DNA-3-methyladenine glycosidase II). This enzyme catalyses only one turnover and therefore is not strictly catalytic.
SYNONYMS
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
Ada protein
-
-
-
-
AGAT
-
-
AGT
Methanocaldococcus jannaschii P2
Q97VW7
-
-
alkylguanine transferase
-
-
alkylguanine transferase
Saccharomyces cerevisiae JD52
-
-
-
ATASE
Escherichia coli BS21
-
-
-
C-hAGT
-
-
carboxyl terminal domain of the inducible Escherichia coli ada alkyltransferase
-
-
methylated-DNA-[protein]-cysteine S-methyltransferase
-
-
methylguanine DNA methyltransferase
-
-
MGMT
-
-
-
-
MGMT
P16455
-
MGMT
Methanocaldococcus jannaschii P2
Q97VW7
-
-
Mgt1
Saccharomyces cerevisiae JD52
-
-
-
N-hAGT
-
-
O6-alkylguanine DNA alkyltransferase
-
-
O6-alkylguanine DNA-alkyltransferase
-
-
O6-alkylguanine-DNA alkyl-transferase
-
-
O6-alkylguanine-DNA alkyltransferase
O67467
-
O6-alkylguanine-DNA alkyltransferase
O27970
-
O6-alkylguanine-DNA alkyltransferase
-
-
O6-alkylguanine-DNA alkyltransferase
Escherichia coli BS21
-
-
-
O6-alkylguanine-DNA alkyltransferase
-
-
O6-alkylguanine-DNA alkyltransferase
-
-
O6-alkylguanine-DNA alkyltransferase
-
-
O6-alkylguanine-DNA alkyltransferase
-
-
O6-alkylguanine-DNA alkyltransferase
Saccharomyces cerevisiae JD52
-
-
-
O6-alkylguanine-DNA alkyltransferase
-
-
O6-methylguanine DNA methyltransferase
-
-
O6-methylguanine-DNA methyltransferase
-
-
-
-
O6-methylguanine-DNA methyltransferase
P16455
-
O6-methylguanine-DNA methyltransferase
-
-
O6-methylguanine-DNA methyltransferase
-
-
O6-methylguanine-DNA methyltransferase
-
-
O6-methylguanine-DNA methyltransferase
-
-
O6-methylguanine-DNA-methyltransferase
-
-
O6-MGMT
-
-
-
-
O6meG-DNA alkyltransferase
-
-
O6meG-DNA alkyltransferase
Saccharomyces cerevisiae JD52
-
-
-
OGT
Methanocaldococcus jannaschii P2
Q97VW7
-
-
SSO2487
Methanocaldococcus jannaschii P2
Q97VW7
locus name
-
SSO2487
Q97VW7
locus name
CAS REGISTRY NUMBER
COMMENTARY
77271-19-3
-
ORGANISM
COMMENTARY
LITERATURE
UNIPROT
SEQUENCE DB
SOURCE
Escherichia coli BS21
-
-
-
Manually annotated by BRENDA team
three allelic variants: V1, V2, and V3
-
-
Manually annotated by BRENDA team
Methanocaldococcus jannaschii P2
-
SwissProt
Manually annotated by BRENDA team
C57BL/6 and F1 (C57BL/6 x 129/Sv) wild-type mice
-
-
Manually annotated by BRENDA team
newborn C57bl/6 mice
-
-
Manually annotated by BRENDA team
Pyrococcus sp. KOD1
KOD1
-
-
Manually annotated by BRENDA team
Saccharomyces cerevisiae JD52
strain JD52
-
-
Manually annotated by BRENDA team
strain HB8
-
-
Manually annotated by BRENDA team
GENERAL INFORMATION
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
malfunction
-
O6-methylguanine-DNA methyltransferase-deficient mice show a higher colon cancer frequency than the wild type
metabolism
-
Mgt1 is a physiological substrate of both the Ubr1-dependent N-end rule pathway and the Ufd4-dependent ubiquitin fusion degradation pathway
metabolism
Saccharomyces cerevisiae JD52
-
Mgt1 is a physiological substrate of both the Ubr1-dependent N-end rule pathway and the Ufd4-dependent ubiquitin fusion degradation pathway
-
physiological function
-
MGMT promoter methylation modulated by p53 status can partially promote p53 mutation occurrence in advanced lung tumors
physiological function
-
O6-methylguanine reversal by the enzyme is required for protection against alkylation-induced colon carcinogenesis
physiological function
-
the DNA repair protein O6-alkylguanine-DNA alkyltransferase is a principal mechanism of cellular resistance to the toxic and mutagenic effects of DNA damage produced by certain monofunctional alkylating agents. ATase operates by the transfer of the offending alkyl groups from the O6 position of guanine and the O4 position of thymine in damaged DNA to a cysteine residue at the active site of the protein. This is an irreversible process that results in the stoichiometric inactivation of the protein
physiological function
Escherichia coli BS21
-
the DNA repair protein O6-alkylguanine-DNA alkyltransferase is a principal mechanism of cellular resistance to the toxic and mutagenic effects of DNA damage produced by certain monofunctional alkylating agents. ATase operates by the transfer of the offending alkyl groups from the O6 position of guanine and the O4 position of thymine in damaged DNA to a cysteine residue at the active site of the protein. This is an irreversible process that results in the stoichiometric inactivation of the protein
-
SUBSTRATE
PRODUCT                      
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate)
LITERATURE
(Substrate)
COMMENTARY
(Product)
LITERATURE
(Product)
Reversibility
r=reversible
ir=irreversible
?=not specified
DNA (containing 6-O-methylguanine) + [protein] L-cysteine
DNA (without 6-O-methylguanine) + [protein] S-methyl-L-cysteine
show the reaction diagram
-
-
-
-
ir
DNA (containing 6-O-methylguanine) + [protein] L-cysteine
DNA (without 6-O-methylguanine) + [protein] S-methyl-L-cysteine
show the reaction diagram
-
the DNA repair protein O6-alkylguanine-DNA alkyltransferase is a principal mechanism of cellular resistance to the toxic and mutagenic effects of DNA damage produced by certain monofunctional alkylating agents. ATase operates by the transfer of the offending alkyl groups from the O6 position of guanine and the O4 position of thymine in damaged DNA to a cysteine residue at the active site of the protein. This is an irreversible process that results in the stoichiometric inactivation of the protein
-
-
ir
DNA (containing 6-O-methylguanine) + [protein] L-cysteine
DNA (without 6-O-methylguanine) + [protein] S-methyl-L-cysteine
show the reaction diagram
-
the DNA repair protein O6-alkylguanine-DNA alkyltransferase is a principal mechanism of cellular resistance to the toxic and mutagenic effects of DNA damage produced by certain monofunctional alkylating agents. ATase operates by the transfer of the offending alkyl groups from the O6 position of guanine and the O4 position of thymine in damaged DNA to a cysteine residue at the active site of the protein. This is an irreversible process that results in the stoichiometric inactivation of the protein
-
-
?
DNA (containing 6-O-methylguanine) + [protein] L-cysteine
DNA (without 6-O-methylguanine) + [protein] S-methyl-L-cysteine
show the reaction diagram
Escherichia coli BS21
-
the DNA repair protein O6-alkylguanine-DNA alkyltransferase is a principal mechanism of cellular resistance to the toxic and mutagenic effects of DNA damage produced by certain monofunctional alkylating agents. ATase operates by the transfer of the offending alkyl groups from the O6 position of guanine and the O4 position of thymine in damaged DNA to a cysteine residue at the active site of the protein. This is an irreversible process that results in the stoichiometric inactivation of the protein
-
-
ir
DNA (containing 6-O-methylguanine) + [protein]-L-cysteine
DNA (without 6-O-methylguanine) + [protein]-S-methyl-L-cysteine
show the reaction diagram
-
-
-
-
?
DNA (containing 6-O-methylguanine) + [protein]-L-cysteine
DNA (without 6-O-methylguanine) + [protein]-S-methyl-L-cysteine
show the reaction diagram
-
-
-
-
?
DNA (containing 6-O-methylguanine) + [protein]-L-cysteine
DNA (without 6-O-methylguanine) + [protein]-S-methyl-L-cysteine
show the reaction diagram
Sulfolobus solfataricus, Methanocaldococcus jannaschii P2
Q97VW7
-
-
-
?
DNA containing 4-O-methylthymine + [protein-L-cysteine
DNA lacking 4-O-methylthymine + [protein]-S-methyl-L-cysteine
show the reaction diagram
-
-
-
-
?
DNA containing 4-O-methylthymine + [protein-L-cysteine
DNA lacking 4-O-methylthymine + [protein]-S-methyl-L-cysteine
show the reaction diagram
-
-
-
-
?
DNA containing 4-O-methylthymine + [protein-L-cysteine
DNA lacking 4-O-methylthymine + [protein]-S-methyl-L-cysteine
show the reaction diagram
-
-
-
-
?
DNA containing 4-O-methylthymine + [protein-L-cysteine
DNA lacking 4-O-methylthymine + [protein]-S-methyl-L-cysteine
show the reaction diagram
-
very poor substrate
-
-
?
DNA containing 4-O-methylthymine + [protein-L-cysteine
DNA lacking 4-O-methylthymine + [protein]-S-methyl-L-cysteine
show the reaction diagram
-
DNA-repair enzyme
-
-
?
DNA containing 4-O-methylthymine + [protein-L-cysteine
DNA lacking 4-O-methylthymine + [protein]-S-methyl-L-cysteine
show the reaction diagram
-
enzyme repairs O6-methylguanine lesions in DNA via alkyl transfer action
-
-
?
DNA containing 4-O-methylthymine + [protein]-L-cysteine
DNA lacking 4-O-methylguanine + [protein]-S-methyl-L-cysteine
show the reaction diagram
-
-
-
-
?
DNA containing 6-O-benzylguanine + [protein]-L-cysteine
DNA lacking 6-O-benzylguanine + [protein]-S-methyl-L-cysteine
show the reaction diagram
-
AGT binds and scans DNA rapidly, flips O6-alkylG residues, transfers the alkyl group in a chemical step that is not rate-limiting in the case of 6-O-benzylguanine and releases the dealkylated DNA
-
-
?
DNA containing 6-O-ethylguanine + [protein]-L-cysteine
DNA lacking 6-O-ethylguanine +[protein]-S-ethyl-L-cysteine
show the reaction diagram
-
CGC(e6G)AGCTCGCG
-
?
DNA containing 6-O-methylguanine + [protein]-L-cysteine
DNA lacking 6-O-methylguanine + [protein]-S-methyl-L-cysteine
show the reaction diagram
-
-
-
-
?
DNA containing 6-O-methylguanine + [protein]-L-cysteine
DNA lacking 6-O-methylguanine + [protein]-S-methyl-L-cysteine
show the reaction diagram
-
-
-
-
?
DNA containing 6-O-methylguanine + [protein]-L-cysteine
DNA lacking 6-O-methylguanine + [protein]-S-methyl-L-cysteine
show the reaction diagram
-
-
-
-
?
DNA containing 6-O-methylguanine + [protein]-L-cysteine
DNA lacking 6-O-methylguanine + [protein]-S-methyl-L-cysteine
show the reaction diagram
-
-
-
-
?
DNA containing 6-O-methylguanine + [protein]-L-cysteine
DNA lacking 6-O-methylguanine + [protein]-S-methyl-L-cysteine
show the reaction diagram
-
-
-
-
?
DNA containing 6-O-methylguanine + [protein]-L-cysteine
DNA lacking 6-O-methylguanine + [protein]-S-methyl-L-cysteine
show the reaction diagram
-
-
-
-
?
DNA containing 6-O-methylguanine + [protein]-L-cysteine
DNA lacking 6-O-methylguanine + [protein]-S-methyl-L-cysteine
show the reaction diagram
-
-
-
-
?
DNA containing 6-O-methylguanine + [protein]-L-cysteine
DNA lacking 6-O-methylguanine + [protein]-S-methyl-L-cysteine
show the reaction diagram
O67467
-
-
-
?
DNA containing 6-O-methylguanine + [protein]-L-cysteine
DNA lacking 6-O-methylguanine + [protein]-S-methyl-L-cysteine
show the reaction diagram
O27970
-
-
-
?
DNA containing 6-O-methylguanine + [protein]-L-cysteine
DNA lacking 6-O-methylguanine + [protein]-S-methyl-L-cysteine
show the reaction diagram
-
-
-
-
?
DNA containing 6-O-methylguanine + [protein]-L-cysteine
DNA lacking 6-O-methylguanine + [protein]-S-methyl-L-cysteine
show the reaction diagram
-
oligonucleotides containing an 6-O-(2-fluorobenzyl)guanine, 6-O-(3-fluorobenzyl)guanine, 6-O-benzylhypoxanthine or 6-O-methylguanine are all good substrates
-
-
?
DNA containing 6-O-methylguanine + [protein]-L-cysteine
DNA lacking 6-O-methylguanine + [protein]-S-methyl-L-cysteine
show the reaction diagram
-
synthetic DNA polymer poly(dC,dG,m6dG)
-
-
?
DNA containing 6-O-methylguanine + [protein]-L-cysteine
DNA lacking 6-O-methylguanine + [protein]-S-methyl-L-cysteine
show the reaction diagram
-
enzyme reacts with the alkylated base in a synthetic DNA substrate poly(dC, dG, m6dG)
-
-
?
DNA containing 6-O-methylguanine + [protein]-L-cysteine
DNA lacking 6-O-methylguanine + [protein]-S-methyl-L-cysteine
show the reaction diagram
-
6-O-methylguanine oligonucleotide
-
-
?
DNA containing 6-O-methylguanine + [protein]-L-cysteine
DNA lacking 6-O-methylguanine + [protein]-S-methyl-L-cysteine
show the reaction diagram
-
the binding to DNA is the rate determining step in the repair process. Approximately eight base pairs of the DNA substrate are covered by the human enzyme. Binding affinity to methylated DNA is two times higher than that to unmodified DNA. The interaction with DNA induces a conformational change in the enzyme
-
-
?
DNA containing 6-O-methylguanine + [protein]-L-cysteine
DNA lacking 6-O-methylguanine + [protein]-S-methyl-L-cysteine
show the reaction diagram
-
CGC(m6G)CG and CGC(m6G)AGCTCGCG
-
-
?
DNA containing 6-O-methylguanine + [protein]-L-cysteine
DNA lacking 6-O-methylguanine + [protein]-S-methyl-L-cysteine
show the reaction diagram
-
the alkyl group is transferred without a cofactor to Cys145 residue of the enzyme and thereby inactivates the protein
-
-
?
DNA containing 6-O-methylguanine + [protein]-L-cysteine
DNA lacking 6-O-methylguanine + [protein]-S-methyl-L-cysteine
show the reaction diagram
-
the methyltransferase protein itself accepts methyl groups from methylated DNA, one enzyme molecule accepts one methyl group
-
-
?
DNA containing 6-O-methylguanine + [protein]-L-cysteine
DNA lacking 6-O-methylguanine + [protein]-S-methyl-L-cysteine
show the reaction diagram
-
the enzyme repairs DNA by transferring alkyl (R)-adducts from 6-O-alkylguanine in DNA to its own cysteine residue at codon 145
-
-
?
DNA containing 6-O-methylguanine + [protein]-L-cysteine
DNA lacking 6-O-methylguanine + [protein]-S-methyl-L-cysteine
show the reaction diagram
-
transferase activity methylates itself on removal of the methyl group from the 6-O position of guanine
-
-
?
DNA containing 6-O-methylguanine + [protein]-L-cysteine
DNA lacking 6-O-methylguanine + [protein]-S-methyl-L-cysteine
show the reaction diagram
-
the enzyme repairs alkylated DNA by suicidal alkyl transfer from guanine 6-O to its own cysteine residue
-
-
?
DNA containing 6-O-methylguanine + [protein]-L-cysteine
DNA lacking 6-O-methylguanine + [protein]-S-methyl-L-cysteine
show the reaction diagram
-
the enzyme functions in DNA repair by direct dealkylation of mutagenic 6-O-alkylguanine. The protein methylated at Cys69 becomes a transcriptional activator of the genes in the ada regulon, including its own
-
-
?
DNA containing 6-O-methylguanine + [protein]-L-cysteine
DNA lacking 6-O-methylguanine + [protein]-S-methyl-L-cysteine
show the reaction diagram
-
the DNA repair enzyme can specifically remove methyl groups from 6-O-methylguanine, which is a major mutagenic and carcinogenic DNA lesion leading to the G-A transition
-
-
?
DNA containing 6-O-methylguanine + [protein]-L-cysteine
DNA lacking 6-O-methylguanine + [protein]-S-methyl-L-cysteine
show the reaction diagram
-
the enzyme is a critical defense against alkylation-induced mutagenesis and carcinogenesis
-
-
?
DNA containing 6-O-methylguanine + [protein]-L-cysteine
DNA lacking 6-O-methylguanine + [protein]-S-methyl-L-cysteine
show the reaction diagram
-
the enzyme repairs mutagenic and carcinogenic 6-O-alkylguanine in DNA
-
-
?
DNA containing 6-O-methylguanine + [protein]-L-cysteine
DNA lacking 6-O-methylguanine + [protein]-S-methyl-L-cysteine
show the reaction diagram
-
6-O-methylguanine is an important adduct formed by methylating agents, that, if not repaired, can lead to mutations and death. Its repair is carried out by 6-O-methylguanine DNA-methyltransferase. Exposure of E. coli cells to sublethal concentrations of methylating agent triggers the expression of the gene
-
-
?
DNA containing 6-O-methylguanine + [protein]-L-cysteine
DNA lacking 6-O-methylguanine + [protein]-S-methyl-L-cysteine
show the reaction diagram
-
DNA hypermethylation and silencing of MGMT are frequent and rather early events in esophageal squamous cell carcinogenesis. Hypermethylation and inactivation of MGMT may be prevented or reversed by dietary polyphenols, (-)-epigallocatechin-3-gallate and genistein, for the prevention of carcinogenesis
-
-
?
DNA containing 6-O-methylguanine + [protein]-L-cysteine
DNA lacking 6-O-methylguanine + [protein]-S-methyl-L-cysteine
show the reaction diagram
O67467
DNA-repair protein that protects cells from killing and mutagenesis by alkylating agents
-
-
?
DNA containing 6-O-methylguanine + [protein]-L-cysteine
DNA lacking 6-O-methylguanine + [protein]-S-methyl-L-cysteine
show the reaction diagram
O27970
DNA-repair protein that protects cells from killing and mutagenesis by alkylating agents
-
-
?
DNA containing 6-O-methylguanine + [protein]-L-cysteine
DNA lacking 6-O-methylguanine + [protein]-S-methyl-L-cysteine
show the reaction diagram
-
key enzyme in DNA repair network. Hypermethylation of the CpG island located in the promoter region of MGMT is primarily responsible for the loss of enzyme function in many tumor types. The methylation mediated silencing of MGMT has two consequences for cancer. First, tumors with MGMT methylation have a new mutator phenotype characterized by the generation of transition point mutations in genes involved in cancer etiology, such as the tumor suppressor p53 and the oncogene K-ras. Second, MGMT hypermethylation demonstrates the possibility of pharmacoepigenomics: methylated tumors are more sensitive to the killing effects of alkylating drugs used in chemotherapy
-
-
?
DNA containing 6-O-methylguanine + [protein]-L-cysteine
DNA lacking 6-O-methylguanine + [protein]-S-methyl-L-cysteine
show the reaction diagram
-
the protein protects the integrity of the genome, and it also contributes to the resistance of tumors to DNA-alkylating chemotherapeutic agents, DNA-binding mechanism
-
-
?
DNA containing 6-O-methylguanine + [protein]-L-cysteine
DNA lacking 6-O-methylguanine + [protein]-S-methyl-L-cysteine
show the reaction diagram
-
AGT binds and scans DNA rapidly, flips O6-alkylG residues, transfers the alkyl group in a chemical step that is rate-limiting in the case of 6-O-methylguanine and releases the dealkylated DNA
-
-
?
DNA containing 6-O-methylguanine + [protein]-L-cysteine
DNA lacking 6-O-methylguanine + [protein]-S-methyl-L-cysteine
show the reaction diagram
-
C-terminal domain is totally inactive, the N-terminal domain has a very weak but definite activity that is totally dependent on the refolding being carried out in the presence of zinc ions
-
-
?
DNA containing 6-O-methylguanine + [protein]-L-cysteine
DNA lacking 6-O-methylguanine + [protein]-S-methyl-L-cysteine
show the reaction diagram
-
prefered substrate
-
-
?
DNA containing 6-O-methylguanine + [protein]-L-cysteine
DNA lacking 6-O-methylguanine + [protein]-S-methyl-L-cysteine
show the reaction diagram
Pyrococcus sp. KOD1
-
-
-
-
?
DNA containing 6-O-methylguanine + [protein]-L-cysteine
DNA lacking 6-O-methylguanine + [protein]-S-methyl-L-cysteine
show the reaction diagram
Saccharomyces cerevisiae JD52
-
-
-
-
?
SNAP-Vista Green + [protein]-L-cysteine
guanine + [protein]-S-Vista Green-L-cysteine
show the reaction diagram
Sulfolobus solfataricus, Methanocaldococcus jannaschii P2
Q97VW7
fluorescent 6-O-benzylguanine derivative
-
-
?
DNA containing O6-(4-oxo-4-(3-pyridyl)butyl)guanine
?
show the reaction diagram
-
-
-
-
?
additional information
?
-
-
the 28-amino acid carboxy-terminal tail of the enzyme is not required for activity and modulates the rate of 6-O-methylguanine DNA methyltransferase repair at reduced temperatures and plays a role in substrate specificity
-
-
-
additional information
?
-
-
binding of AGT to single-stranded DNAs ranging in length from 5 to 78 nucleotides, binding is moderately cooperative, resulting in an all-or-nothing association pattern on short templates binding density
-
-
-
additional information
?
-
-
in addition to repairing methyl groups, longer alkyl groups including ethyl-, n-propyl-, n-butyl-, 2-chloroethyl-, 2-hydroxyethyl-, iso-propyl and iso-butyl can be repaired
-
-
-
additional information
?
-
-
low reactivity of the non-natural substrate O6-propargylguanine with AGT, most likely arises from the poor binding of the substrate to the active site of AGT
-
-
-
additional information
?
-
-
human AGT acts poorly on DNA containing 4-O-methylthymine
-
-
-
additional information
?
-
-
in the catalytic demethylation of DNA containing 6-O-methylguanine, roles of six amino acids, i.e., Cys145, His146, Glu172, Tyr114, Lys165, and Ser159 are involved. At the first step, Cys145 in the Cys145-water-His146-Glu172 tetrad is converted to cysteine thiolate anion while at the second step, abstraction of the Tyr114 proton by the N3 site of DNA containing 6-O-methylguanine occurs in a barrierless manner. In the third step, abstraction of Lys165 proton by deprotonated Tyr114 and transfer of the methyl group of DNA containing 6-O-methylguanine to the thiolate group of Cys145 anion occur simultaneously.
-
-
-
additional information
?
-
-
TTHA1564 can bind to DNA containing 6-O-methylguanine with higher affinity (9fold) than normal (unmethylated) DNA, but TTHA1564 alone does not possess methyltransferase activity, TTHA1564 can interact with nucleotide excision repair proteins and RNA polymerase
-
-
-
NATURAL SUBSTRATES
NATURAL PRODUCTS
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate)
LITERATURE
(Substrate)
COMMENTARY
(Product)
LITERATURE
(Product)
REVERSIBILITY
r=reversible
ir=irreversible
?=not specified
DNA (containing 6-O-methylguanine) + [protein] L-cysteine
DNA (without 6-O-methylguanine) + [protein] S-methyl-L-cysteine
show the reaction diagram
-
the DNA repair protein O6-alkylguanine-DNA alkyltransferase is a principal mechanism of cellular resistance to the toxic and mutagenic effects of DNA damage produced by certain monofunctional alkylating agents. ATase operates by the transfer of the offending alkyl groups from the O6 position of guanine and the O4 position of thymine in damaged DNA to a cysteine residue at the active site of the protein. This is an irreversible process that results in the stoichiometric inactivation of the protein
-
-
ir
DNA (containing 6-O-methylguanine) + [protein] L-cysteine
DNA (without 6-O-methylguanine) + [protein] S-methyl-L-cysteine
show the reaction diagram
-
the DNA repair protein O6-alkylguanine-DNA alkyltransferase is a principal mechanism of cellular resistance to the toxic and mutagenic effects of DNA damage produced by certain monofunctional alkylating agents. ATase operates by the transfer of the offending alkyl groups from the O6 position of guanine and the O4 position of thymine in damaged DNA to a cysteine residue at the active site of the protein. This is an irreversible process that results in the stoichiometric inactivation of the protein
-
-
?
DNA (containing 6-O-methylguanine) + [protein] L-cysteine
DNA (without 6-O-methylguanine) + [protein] S-methyl-L-cysteine
show the reaction diagram
Escherichia coli BS21
-
the DNA repair protein O6-alkylguanine-DNA alkyltransferase is a principal mechanism of cellular resistance to the toxic and mutagenic effects of DNA damage produced by certain monofunctional alkylating agents. ATase operates by the transfer of the offending alkyl groups from the O6 position of guanine and the O4 position of thymine in damaged DNA to a cysteine residue at the active site of the protein. This is an irreversible process that results in the stoichiometric inactivation of the protein
-
-
ir
DNA (containing 6-O-methylguanine) + [protein]-L-cysteine
DNA (without 6-O-methylguanine) + [protein]-S-methyl-L-cysteine
show the reaction diagram
-
-
-
-
?
DNA (containing 6-O-methylguanine) + [protein]-L-cysteine
DNA (without 6-O-methylguanine) + [protein]-S-methyl-L-cysteine
show the reaction diagram
-
-
-
-
?
DNA (containing 6-O-methylguanine) + [protein]-L-cysteine
DNA (without 6-O-methylguanine) + [protein]-S-methyl-L-cysteine
show the reaction diagram
Sulfolobus solfataricus, Methanocaldococcus jannaschii P2
Q97VW7
-
-
-
?
DNA containing 4-O-methylthymine + [protein-L-cysteine
DNA lacking 4-O-methylthymine + [protein]-S-methyl-L-cysteine
show the reaction diagram
-
DNA-repair enzyme
-
-
?
DNA containing 4-O-methylthymine + [protein-L-cysteine
DNA lacking 4-O-methylthymine + [protein]-S-methyl-L-cysteine
show the reaction diagram
-
enzyme repairs O6-methylguanine lesions in DNA via alkyl transfer action
-
-
?
DNA containing 6-O-methylguanine + [protein]-L-cysteine
DNA lacking 6-O-methylguanine + [protein]-S-methyl-L-cysteine
show the reaction diagram
-
-
-
-
?
DNA containing 6-O-methylguanine + [protein]-L-cysteine
DNA lacking 6-O-methylguanine + [protein]-S-methyl-L-cysteine
show the reaction diagram
-
-
-
-
?
DNA containing 6-O-methylguanine + [protein]-L-cysteine
DNA lacking 6-O-methylguanine + [protein]-S-methyl-L-cysteine
show the reaction diagram
-
the enzyme repairs DNA by transferring alkyl (R)-adducts from 6-O-alkylguanine in DNA to its own cysteine residue at codon 145
-
-
?
DNA containing 6-O-methylguanine + [protein]-L-cysteine
DNA lacking 6-O-methylguanine + [protein]-S-methyl-L-cysteine
show the reaction diagram
-
the enzyme functions in DNA repair by direct dealkylation of mutagenic 6-O-alkylguanine. The protein methylated at Cys69 becomes a transcriptional activator of the genes in the ada regulon, including its own
-
-
?
DNA containing 6-O-methylguanine + [protein]-L-cysteine
DNA lacking 6-O-methylguanine + [protein]-S-methyl-L-cysteine
show the reaction diagram
-
the DNA repair enzyme can specifically remove methyl groups from 6-O-methylguanine, which is a major mutagenic and carcinogenic DNA lesion leading to the G-A transition
-
-
?
DNA containing 6-O-methylguanine + [protein]-L-cysteine
DNA lacking 6-O-methylguanine + [protein]-S-methyl-L-cysteine
show the reaction diagram
-
the enzyme is a critical defense against alkylation-induced mutagenesis and carcinogenesis
-
-
?
DNA containing 6-O-methylguanine + [protein]-L-cysteine
DNA lacking 6-O-methylguanine + [protein]-S-methyl-L-cysteine
show the reaction diagram
-
the enzyme repairs mutagenic and carcinogenic 6-O-alkylguanine in DNA
-
-
?
DNA containing 6-O-methylguanine + [protein]-L-cysteine
DNA lacking 6-O-methylguanine + [protein]-S-methyl-L-cysteine
show the reaction diagram
-
6-O-methylguanine is an important adduct formed by methylating agents, that, if not repaired, can lead to mutations and death. Its repair is carried out by 6-O-methylguanine DNA-methyltransferase. Exposure of E. coli cells to sublethal concentrations of methylating agent triggers the expression of the gene
-
-
?
DNA containing 6-O-methylguanine + [protein]-L-cysteine
DNA lacking 6-O-methylguanine + [protein]-S-methyl-L-cysteine
show the reaction diagram
-
DNA hypermethylation and silencing of MGMT are frequent and rather early events in esophageal squamous cell carcinogenesis. Hypermethylation and inactivation of MGMT may be prevented or reversed by dietary polyphenols, (-)-epigallocatechin-3-gallate and genistein, for the prevention of carcinogenesis
-
-
?
DNA containing 6-O-methylguanine + [protein]-L-cysteine
DNA lacking 6-O-methylguanine + [protein]-S-methyl-L-cysteine
show the reaction diagram
O67467
DNA-repair protein that protects cells from killing and mutagenesis by alkylating agents
-
-
?
DNA containing 6-O-methylguanine + [protein]-L-cysteine
DNA lacking 6-O-methylguanine + [protein]-S-methyl-L-cysteine
show the reaction diagram
O27970
DNA-repair protein that protects cells from killing and mutagenesis by alkylating agents
-
-
?
DNA containing 6-O-methylguanine + [protein]-L-cysteine
DNA lacking 6-O-methylguanine + [protein]-S-methyl-L-cysteine
show the reaction diagram
-
key enzyme in DNA repair network. Hypermethylation of the CpG island located in the promoter region of MGMT is primarily responsible for the loss of enzyme function in many tumor types. The methylation mediated silencing of MGMT has two consequences for cancer. First, tumors with MGMT methylation have a new mutator phenotype characterized by the generation of transition point mutations in genes involved in cancer etiology, such as the tumor suppressor p53 and the oncogene K-ras. Second, MGMT hypermethylation demonstrates the possibility of pharmacoepigenomics: methylated tumors are more sensitive to the killing effects of alkylating drugs used in chemotherapy
-
-
?
DNA containing 6-O-methylguanine + [protein]-L-cysteine
DNA lacking 6-O-methylguanine + [protein]-S-methyl-L-cysteine
show the reaction diagram
-
the protein protects the integrity of the genome, and it also contributes to the resistance of tumors to DNA-alkylating chemotherapeutic agents
-
-
?
DNA containing 6-O-methylguanine + [protein]-L-cysteine
DNA lacking 6-O-methylguanine + [protein]-S-methyl-L-cysteine
show the reaction diagram
Saccharomyces cerevisiae JD52
-
-
-
-
?
COFACTOR
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
additional information
-
the enzyme requires no cofactor
-
METALS and IONS
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
Zinc
-
in bacterial expression systems, recombinant hAGT is produced in increasingly larger quantities when growth media are supplemented with up to 0.1 mM ZnCl2. Metal-enriched hAGT samples have a 5fold increase in repair rate constant over conventionally purified protein samples and a 60fold increase over metal-stripped hAGT. Zinc confers a mechanistic enhancement to repair activity that does not result from an increase in substrate binding affinity. Zinc also provides conformational stability to hAGT that may influence its regulation
Zn2+
-
Cys145 in hAGT exists as a reactive thiolate anion at neutral pH. The low pKa of Cys145 is dependent upon the bound Zn2+
Zn2+
-
N-terminal domain contains a bound zinc atom, and zinc binding confers a mechanistic enhancement to repair activity
INHIBITORS
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
2-([2-amino-6-[(4-bromothiophen-2-yl)methoxy]-9H-purin-9-yl]methoxy)ethanol
-
-
2-amino-O4-benzyl-6,7-dimethylpteridine
-
potent
2-amino-O4-benzyl-6-formylpteridine
-
potent
2-amino-O4-benzyl-6-hydroxymethylpteridine
-
potent
2-amino-O4-benzylpteridine
-
potent
2-amino-O4-benzylpteridine-6-carboxylic acid
-
potent
4-[(4-bromothiophen-2-yl)methoxy]-1H-pyrazolo[3,4-d]pyrimidin-6-amine
-
-
4-[bis(2-chloroethyl)amino]-L-phenylalanine
-
hyperthermia enhances the inhibitory effects of L-phenylalanine mustard on melanoma cell growth
6-(1-benzofuran-2-ylmethoxy)-9H-purin-2-amine
-
-
6-(4,5,6,7-tetrahydro-1-benzothiophen-2-ylmethoxy)-9H-purin-2-amine
-
-
6-(naphtho[1,2-b]thiophen-2-ylmethoxy)-9H-purin-2-amine
-
-
6-(naphtho[2,1-b]thiophen-2-ylmethoxy)-9H-purin-2-amine
-
-
6-(phenanthro[9,10-b]thiophen-2-ylmethoxy)-9H-purin-2-amine
-
-
6-O-benzylguanine
Q97VW7
-
6-[(1-methyl-4-nitro-1H-pyrrol-2-yl)methoxy]-9H-purin-2-amine
-
-
6-[(4-bromothiophen-2-yl)methoxy]-9-(2-deoxy-beta-D-erythro-pentofuranosyl)-9H-purin-2-amine
-
-
7-[(4-bromothiophen-2-yl)methoxy]-2,3-dihydro-1H-[1,2,3]triazolo[4,5-d]pyrimidin-5-amine
-
-
9-beta-D-arabinofuranosyl-6-[(4-bromothiophen-2-yl)methoxy]-9H-purin-2-amine
-
-
alkyltransferase-like protein
-
inhibits the transfer of methyl groups to MGMT, thus the action of MGMT on 6-O-methylguanine in DNA, inhibition is reversible by prolonged incubation in the presence of MGMT
-
Br(CH2)2Br
-
inactivates purified AGT and mutant R128A to approximately the same extent; inactivates purified AGT and mutant R128A to approximately the same extent, small reduction in the loss of activity in the absence of DNA, but no effect at all in the presence of DNA, inactivates mutant Y114A much less than wild-type, and DNA completely prevents this inactivation, mutants P140K and Y158H are less inactivated than wild-type AGT, specifically in the presence of DNA
Br(CH2)3Br
-
mutant P140K requires higher concentrations than wild-type AGT for inactivation
Br(CH2)5Br
-
mutant P140K requires higher concentrations than wild-type AGT for inactivation
BrCH2Br
-
wild-type AGT and mutant P140K show no difference in sensitivity to BrCH2Br
BrCH2OAc
-
reacts with the enzyme at its cysteine acceptor site, abolishing its DNA repair activity, the formation of AGT-Cys145S-CH2Br by BrCH2OAc
CH2Br2
-
reacts with the enzyme at its cysteine acceptor site, abolishing its DNA repair activity
double-stranded oligonucleotides
-
6-O-methylguanine, 6-O-(4-fluorobenzyl)-guanine, 6-O-(3-fluorobenzyl)-guanine, 6-O-(2-fluorobenzyl)-guanine, 6-O-benzylguanine, 6-O-benzylhypoxanthine. IC50: 1.4-3.0 nM
-
formaldehyde
-
decreases activity at levels up to 3fold higher than the maximally allowed workplace concentration, no decrease at the maximally allowed level
Methyl iodide
-
can directly alkylate the active site of the enzyme, the agent can increase the effectiveness of environmental and endogenously produced alkylating carcinogens in producing the mutagenic 6-O-alkylguanine residue in DNA in vivo
N9-cyclopentyl-O6-(4-bromothenyl)guanine
-
efficient inhibitor of wild-type AGT
Na3 citrate
-
-
NaCl
-
0.2 M, 80% inhibition
NaCl
-
0.2 M, wild-type and mutant enzyme, 55% inhibition
Ni2+
-
purified protein is not very sensitive to this metal but the loss of AGT could contribute to the well-known carcinogenicity of nickel
O(6)-benzylguanine
-
BG
O4-(4-bromothenylpterin)
-
-
O4-benzylfolic acid
-
30times more active than O6-benzylguanine against the wild-type alkyltransferase, inactivation of P140K mutant alkyltransferase. Inhibitor shows promise as an agent for possible tumor-selective alkyltransferase inactivation superior toO6-benzylguanine as a chemotherapy adjuvant
O6-(1,2-thiazol-4-ylmethyl)guanine
-
-
O6-(1,3-oxazol-5-yl)guanine
-
-
O6-(1,3-thiazol-5-yl)guanine
-
-
O6-(1-benzofuran-2-ylmethyl)guanine
-
-
O6-(2-benzo[b]thienylmethyl)guanine
-
-
O6-(3-pyridyl)guanine
-
-
O6-(4-(2-chloropyridyl))guanine
-
-
O6-(4-bromothenyl)-8-oxaguanine
-
-
O6-(4-bromothenyl)-8-thiaguanine
-
-
O6-(4-bromothenyl)guanine
-
-
O6-(4-bromothenyl)guanine
-
most potent inactivator described to date
O6-(4-bromothenyl)guanine
-
pseudosubstrate, direct inhibitor
O6-(4-bromothenyl)guanine
-
PaTrin, PaTrin-2, Lomeguatrib
O6-(4-pyridyl)guanine
-
-
O6-alkylating drugs
-
O6-alkylating drugs deplete MGMT activity indirectly via alkylation of DNA
-
O6-benzyl-2'-deoxyguanosine
-
-
O6-benzylguanine
O67467
-
O6-benzylguanine
O27970
-
O6-benzylguanine
-
potent inhibitor of wild-type enzyme, no inactivation of mutant enzyme P140K
O6-benzylguanine
-
pretreatment of Mgmt+/+ mice prior to 1,3-bis (2-chloroethyl)-1-nitrosourea does not result in significantly more mutations than mice treated with 1,3-bis (2-chloroethyl)-1-nitrosourea alone
O6-benzylguanine
-
mutants P140K and Y158H are the most resistant
O6-benzylguanine
-
binds in the active site pocket, abolishes resistance against therapeutic agents temozolomide and N,N'-bis(2-chloroethyl)-N-nitrosourea
O6-benzylguanine
-
pseudosubstrate, direct inhibitor
O6-benzylguanine
-
a synthetic MGMT inhibitor
O6-furfurylguanine
-
-
O6-methylguanine
-
-
O6-methylguanine oligonucleotide
-
preincubation of extracts with a short oligonucleotide containing a single O6-methylguanine residue causes essentially complete loss of ATase activity
-
O6-thenylguanine
-
original Patrin, became Patrin-1
O6-[(1-methyl-1H-imidazol-5-yl)methyl]guanine
-
-
temozolomide
-
treatment for 5 days depletes MGMT in peripheral mononuclear cells in at least 76% of patients and low MGMT activity is correlated with severe thrombocytopenia during the first treatment cycle
temozolomide
-
TMZ; tumor cells with high levels of MGMT and/or with a defective DNA mismatch repair are resistant to temozolomide, hyperthermia significantly enhances temozolomide cytotoxicity in mismatch repair-proficient cells, either endowed or not with MGMT activity, and in mismatch repair-deficient cells, hyperthermia alone does not affect MGMT activity, but enhances the enzyme depletion induced by temozolomide treatment
temozolomide
-
TMZ
VNP40101M
-
methyl isocyanate resulting from base-catalyzed activation of VNP40101M inhibits the enzyme, thereby enhancing the yield of the DNA G-C interstrand crosslink responsible for the antitumor activity of this agent
methyl isocyanate
-
methyl isocyanate resulting from base-catalyzed activation of VNP40101M inhibits the enzyme, thereby enhancing the yield of the DNA G-C interstrand crosslink responsible for the antitumor activity of this agent
additional information
-
transferase activity methylates itself on removal of the methyl group from the 6-O position of guanine. Modification of a reactive sulfhydryl group can account for the enzyme inactivation accompanying the reaction
-
additional information
-
the enzyme repairs alkylated DNA by suicidal alkyl transfer from guanine 6-O to its own Cys residue
-
additional information
-
the alkyl group is transferred without a cofactor to Cys145 residue of the enzyme and thereby inactivates the protein
-
additional information
-
high level of enzyme in tumors and relative resistance to cyclophosphamide in lung cancer indicates that 6-O-methylguanine-DNA methyltransferase may be a predictive factor of resistance to cyclophosphamide
-
additional information
-
substances present in the saliva of tobacco and betel nut chewers
-
additional information
-
hydroxyethyl guanine-modified oligodeoxyribonucleotides are not effective inactivators of MGMT
-
additional information
-
epigenetic silencing by promoter methylation, it has been reported that the E1A gene product of adenovirus efficiently inhibits the promoter activity of MGMT
-
ACTIVATING COMPOUND
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
1,2,3,4-diepoxybutane
-
induces AGT-DNA cross-linking, takes place exclusively at the cysteine residues within the protein
activator of protein kinase C
-
increases the level of AGT mRNA and increases resistance to N,N'-bis(2-chloroethyl)-N-nitrosourea in HeLa cells
-
dexamethasone
-
-
glucocorticoid
-
regulates AGT expression
-
glucocorticoid
-
-
-
inhibitor of protein phosphatase
-
increases the level of AGT mRNA and increases resistance to N,N'-bis(2-chloroethyl)-N-nitrosourea in HeLa cells
-
N,N'-bis(2-chloroethyl)-N-nitrosourea
-
BCNU
P53
-
regulates MGMT promoter
P53
-
controversly discussed
ionizing radiation
-
induces AGT
-
additional information
-
DNA damage, ionizing radiation
-
KM VALUE [mM]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
0.01
SNAP-Vista Green
Q97VW7
pH 6.5, 50C
0.00077
DNA (containing 6-O-methylguanine)
Q97VW7
pH 6.5, 50C
additional information
additional information
-
-
-
TURNOVER NUMBER [1/s]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
8.4
SNAP-Vista Green
Q97VW7
pH 6.5, 50C
additional information
additional information
-
second order repair rate constants of 6-O-methyl and 6-O-ethylguanine containing substrates
-
IC50 VALUE [mM]
INHIBITOR
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
0.00033
2-([2-amino-6-[(4-bromothiophen-2-yl)methoxy]-9H-purin-9-yl]methoxy)ethanol
-
-
0.000006
4-[(4-bromothiophen-2-yl)methoxy]-1H-pyrazolo[3,4-d]pyrimidin-6-amine
-
-
0.00008
6-(1-benzofuran-2-ylmethoxy)-9H-purin-2-amine
-
-
0.185
6-(4,5,6,7-tetrahydro-1-benzothiophen-2-ylmethoxy)-9H-purin-2-amine
-
-
0.000022
6-(naphtho[1,2-b]thiophen-2-ylmethoxy)-9H-purin-2-amine
-
-
0.00005
6-(naphtho[2,1-b]thiophen-2-ylmethoxy)-9H-purin-2-amine
-
-
0.0011
6-(phenanthro[9,10-b]thiophen-2-ylmethoxy)-9H-purin-2-amine
-
-
0.00055
6-[(1-methyl-4-nitro-1H-pyrrol-2-yl)methoxy]-9H-purin-2-amine
-
-
0.000095
6-[(4-bromothiophen-2-yl)methoxy]-9-(2-deoxy-beta-D-erythro-pentofuranosyl)-9H-purin-2-amine
-
-
0.000045
7-[(4-bromothiophen-2-yl)methoxy]-2,3-dihydro-1H-[1,2,3]triazolo[4,5-d]pyrimidin-5-amine
-
-
0.000115
9-beta-D-arabinofuranosyl-6-[(4-bromothiophen-2-yl)methoxy]-9H-purin-2-amine
-
-
0.0000014 - 0.000003
double-stranded oligonucleotides
-
6-O-methylguanine, 6-O-(4-fluorobenzyl)-guanine, 6-O-(3-fluorobenzyl)-guanine, 6-O-(2-fluorobenzyl)-guanine, 6-O-benzylguanine, 6-O-benzylhypoxanthine. IC50: 1.4-3.0 nM
-
0.0005
N9-cyclopentyl-O6-(4-bromothenyl)guanine
-
-
0.000025
O4-(4-bromothenylpterin)
-
-
0.00007
O6-(1,2-thiazol-4-ylmethyl)guanine
-
-
0.00035
O6-(1,3-oxazol-5-yl)guanine
-
-
0.000033
O6-(1,3-thiazol-5-yl)guanine
-
-
0.000035
O6-(1-benzofuran-2-ylmethyl)guanine
-
-
0.00003
O6-(2-benzo[b]thienylmethyl)guanine
-
-
0.00043
O6-(3-pyridyl)guanine
-
-
0.00004
O6-(4-(2-chloropyridyl))guanine
-
-
0.00024
O6-(4-bromothenyl)-8-oxaguanine
-
-
0.0000028
O6-(4-bromothenyl)-8-thiaguanine
-
-
0.0000001
O6-(4-bromothenyl)guanine
-
-
0.0000034
O6-(4-bromothenyl)guanine
-
Patrin, PaTrin-2, Lomeguatrib
0.00013
O6-(4-pyridyl)guanine
-
-
0.00009
O6-benzylguanine
-
N-hAGT and C-hAGT complex
0.0001
O6-benzylguanine
-
wild-type
0.0002
O6-benzylguanine
-
-
0.00022
O6-benzylguanine
-
N-hAGT
0.004
O6-benzylguanine
-
mutant P140A
0.005
O6-benzylguanine
-
mutant G160R
0.015
O6-benzylguanine
-
mutant G156A
0.62
O6-benzylguanine
-
mutant Y158H
1.2
O6-benzylguanine
-
mutant P140K
0.0003
O6-furfurylguanine
-
-
0.000018
O6-thenylguanine
-
-
0.0085
O6-[(1-methyl-1H-imidazol-5-yl)methyl]guanine
-
-
SPECIFIC ACTIVITY [µmol/min/mg]
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
additional information
-
-
additional information
-
developmemt of a novel fluorometric oligonucleotide assay to measure enzyme activity in cellular and tissue extracts
additional information
-
-
additional information
-
M14 cell line, 136, PR-Mel cell line 15 fmol of 3H-methyl groups transferred per mg of protein in cell extract
pH OPTIMUM
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
pH RANGE
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
4.5 - 9.5
Q97VW7
-
6 - 7.6
-
pH 6.0: about 80% of maximal activity, pH 7.6: about 40% of maximal activity
TEMPERATURE RANGE
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
15 - 40
-
about 75% of maximal activity at 15 or at 40C
20 - 90
Q97VW7
-
37 - 70
-
about 50% of maximal activitya at 37C and at 70C
50 - 100
-
activity increases from 50C to 100%, 60C: about 45% of the activity at 100C, 50% about 15% of maximal activity
60 - 100
-
activity at 60C is about 35% of the activity at 100C
65 - 85
-
65C: about 50% of maximal activity, 85C: about 45% of maximal activity
80 - 100
O27970
80C: optimum, 100C: substantial repair activity at
SOURCE TISSUE
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
SOURCE
-
low activity
Manually annotated by BRENDA team
-
level of AGT is much reduced in mice lacking p53
Manually annotated by BRENDA team
-
MGMT gene expression is substantially lower in knockout p53 astrocytes than in wild-type p53 astrocytes
Manually annotated by BRENDA team
-
AGT expression is increased in breast cancer compared to normal breast
Manually annotated by BRENDA team
-
activity is significantly decreased in samples from current smokers compared to nonsmokers
Manually annotated by BRENDA team
-
activity in cells adapted by exposure to N-methyl-N1-nitroguanidine, no activity in extracts of nonadapted cells
Manually annotated by BRENDA team
-
esophageal squamous cell carcinoma
Manually annotated by BRENDA team
-
lowered in cirrhotic liver
Manually annotated by BRENDA team
-
MGMT is ubiquitously expressed, the liver expresses the highest levels and haematopoietic tissues and brain the lowest
Manually annotated by BRENDA team
-
increased in lung cancers from smokers rather than non-smokers
Manually annotated by BRENDA team
-
no statistically significant difference in the amount of enzyme between tumors with and without activated H1-ras oncogene
Manually annotated by BRENDA team
-
D283 MED, D341 MED and Daoy
Manually annotated by BRENDA team
-
three lines with different MGMT activity and functional status of the mismatch repair system
Manually annotated by BRENDA team
-
low 6-O-methylguanine-DNA methyltransferase activity may contribute to the chemosensitivity of some human oligodendrogliomas
Manually annotated by BRENDA team
-
MGMT activity is significantly lower in bronchial epithelial cells than in PBMC cells
Manually annotated by BRENDA team
additional information
-
3T3 cell line has an amplification of the MGMT gene
Manually annotated by BRENDA team
additional information
-
absent from brain
Manually annotated by BRENDA team
additional information
-
malignant glioma cell
Manually annotated by BRENDA team
additional information
-
PR-Mel cell and GL-Mel-D2 cell
Manually annotated by BRENDA team
LOCALIZATION
ORGANISM
UNIPROT
COMMENTARY
GeneOntology No.
LITERATURE
SOURCE
Methanocaldococcus jannaschii P2
-
-
-
Manually annotated by BRENDA team
-
mainly localized in the nucleus
Manually annotated by BRENDA team
PDB
SCOP
CATH
ORGANISM
Escherichia coli (strain K12)
Methanocaldococcus jannaschii (strain ATCC 43067 / DSM 2661 / JAL-1 / JCM 10045 / NBRC 100440)
Mycobacterium tuberculosis (strain ATCC 25618 / H37Rv)
Mycobacterium tuberculosis (strain ATCC 25618 / H37Rv)
Sulfolobus tokodaii (strain DSM 16993 / JCM 10545 / NBRC 100140 / 7)
Thermococcus kodakaraensis (strain ATCC BAA-918 / JCM 12380 / KOD1)
MOLECULAR WEIGHT
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
17040
Q97VW7
amino acid sequence
717873
19000
-
gel filtration, glycerol density gradient sedimentation
485505
21000
-
SDS-PAGE
706528
23000
O67467
-
657833
23000
-
-
673219
51000
-
enhanced green fluorescent protein-tagged enzyme, SDS-PAGE
705897
SUBUNITS
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
?
-
x * 16000, SDS-PAGE
?
-
x * 39000, SDS-PAGE
?
-
x * 24000, SDS-PAGE
?
-
x * 23000, SDS-PAGE
?
-
x * 22000, SDS-PAGE
?
-
x * 20900, SDS-PAGE
?
-
x * 39356, inactive enzyme, electrospray mass spectrometry, x * 39377, active enzyme, electrospray mass spectrometry
?
-
x * 22500, SDS-PAGE
?
-
x * 15000, SDS-PAGE
?
O27970
x * 16718, calculation from nucleotide sequence
?
-
x * 21860, SDS-PAGE, x * 21614, sequence analysis
?
Escherichia coli BS21
-
x * 39000, SDS-PAGE
-
monomer
Q97VW7
-
monomer
-
1 * 25000, SDS-PAGE
monomer
Methanocaldococcus jannaschii P2
-
-
-
additional information
-
structure analysis by multinuclear multidimensional NMR spectroscopy, a two-domain protein with an alpha/beta fold, N-terminal domain consists of a three-stranded antiparallel beta sheet, N-terminus is somewhat less well defined than the C-terminus, structure is similar to homologs from other organisms that have been determined by crystallography, with some variation in the N-terminal domain, whereas the C-terminal domain is more highly conserved in both sequence and structure
Crystallization/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
Cys acceptor site is buried in the protein and, in order for reaction with a DNA substrate to take place, a change in conformation of either the substrate or the protein must occur, Glu-172 and Asn-137 play a major structural role in the AGT protein
-
crystals formed at 20C by conventional hanging drop-vapor diffusion method
-
TEMPERATURE STABILITY
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
37
-
spontaneously loses about 30% of its secondary structure in less than 30 min concomitant with a complete loss of activity
485504
37
-
t1/2: 38 h
726406
37
-
t1/2: 60 h
726406
37
-
t1/2: 32 h
726406
37
-
t1/2: 72 h
726406
50
-
20 min, 55-65% loss of activity in absence of DNA, 25-35% loss of activity in presence of DNA, 0.2 mg/ml
485500
60
O67467
half-life: 12 h
657833
60
O27970
half-life: 24 h
657833
60
Q97VW7
half life of 257 min
717873
60
-
t1/2: 12 h
726406
60
-
t1/2: 40 h
726406
60
-
t1/2: 16 h
726406
60
-
t1/2: 18 h
726406
65
-
5 min, almost complete inactivation
485494
70
-
protein immediately coagulates
485504
70
Q97VW7
half life of 165 min
717873
75
-
60 min, 25% loss of activity
485495
80
Q97VW7
half life of 19 min
717873
80
-
t1/2: 5.5 h
726406
80
-
t1/2: 5 h
726406
80
-
t1/2: 0.5 h
726406
80
-
t1/2: 13 h
726406
90
-
stable for at least 30 min. 66% loss of activity after 60 min
485495
additional information
-
enzyme is extremely thermostable
485488
additional information
-
temperature-dependent inactivation of the enzyme is inhibited by DNA
485504
GENERAL STABILITY
ORGANISM
UNIPROT
LITERATURE
enzyme is denatured by 8 M urea at pH 7.5 for 30 s or by 6 M guanidine hydrochloride at pH 7.5 for 16-24 h
-
zinc provides conformational stability to hAGT that may influence its regulation
-
very stable to proteases attack and detergents such as Triton X-100
Q97VW7
guanidine-HCl, half-time for unfolding at 30C is 52 days. An ion-pair network plays a key role in the slow unfolding
-
ORGANIC SOLVENT
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
2,2,2-trifluoroethanol
-
enzyme retains its native structure at high concentrations
2-propanol
-
enzyme retains its native structure at high concentrations
Ethanol
-
enzyme retains its native structure at high concentrations
Methanol
-
enzyme retains its native structure at high concentrations
SDS
-
enzyme retains its native structure at high concentrations
urea
-
5 mM, melting temperature of wild-type enzyme: 91.5 C, melting temperature of mutant enzyme E83A: 89.2C, melting temperature of mutant enzyme E93A: 85.5C, melting temperature of mutant enzyme E158A: 90.6C, melting temperature of mutant enzyme E159A: 91.7 C
STORAGE STABILITY
ORGANISM
UNIPROT
LITERATURE
4C, stored at, storage at -20C or at -80C results in protein precipitation
O67467
4C, stored at, storage at -20C or at -80C results in protein precipitation
O27970
-20C stable for years
Q97VW7
Purification/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
expressed at high levels in Escherichia coli fused to an N-terminal polyhistidine tag that allows a single-step isolation and purification by metal-affinity chromatography
O67467
expressed at high levels in Escherichia coli fused to an N-terminal polyhistidine tag that allows a single-step isolation and purification by metal-affinity chromatography
O27970
immobilized metal affinity column chromatography
-
mutant V139F
-
by immobilized metal affinity chromatography
-
immobilized metal affinity column chromatography
-
mutants purified by either nickel or glutathione affinity chromatography
-
recombinant enzyme
-
to apparent homogeneity
-
recombinant enzyme
-
Ni-NTA resin column chromatography, gel filtration
-
heterologous expression by His-tag chromatography affinity
Q97VW7
amylose resin column chromatography, Toyopearl-SuperQ column chromatography, ammonium sulfate precipitation, and Toyopearl-ether 650M column chromatography
-
Cloned/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
expressed at high levels in Escherichia coli fused to an N-terminal polyhistidine tag that allows a single-step isolation and purification by metal-affinity chromatography
O67467
expressed at high levels in Escherichia coli fused to an N-terminal polyhistidine tag that allows a single-step isolation and purification by metal-affinity chromatography
O27970
expressed in Escherichia coli XL-1 Blue cells
-
expression in Escherichia coli
-
cDNA is cloned into a pET-11a plasmid and expressed in Escherichia coli
-
expressed in CHO-9 cells
-
expressed in Escherichia coli
-
expressed in Escherichia coli XL-1 Blue cells
-
expressed in Escherichia coliKT233 and in HeLa cells
-
expressed in HEK-293T cells as enhanced green fluorescent protein-tagged enzyme
-
expression in CHO cells
-
expression in Escherichia coli strain AB1157 and isogenic strain GWR111
-
expression in Escherichia coli TRG8
-
expression in Escherichia coli, transgenic overexpression in mouse skin, expression in CHO cells
-
expression of N-hAGT and C-hAGT in Escherichia coli XL1-Blue cells. N-hAGT, C-hAGT and full length AGT expressed from the pQE-30 vector in Escherichia coli GWR-109
-
ligated into the pHybLex/Zeo plasmid and electroporated into Escherichia coli XL1-Blue, yielding a library of at least 320000 independent clones, genes of selected AGT mutants subcloned into the pGEX-2T plasmid, allowing for the expression of the AGT mutants as GST fusion proteins
-
mutants subcloned into pGEX-2T for expression as a GSTAGT fusion, or into pET15b for expression as a 6 x HisAGT fusion protein
-
overexpressed in Escherichia coli strain UC978
-
overexpression in CHO-derived Tet-on-inducible cells, knockdown of MGMT expression with small interfering RNA in HONE-1 cells
-
recombinant AGT and mutants expressed in Escherichia coli, pQE expression vectors for wild-type and mutant AGT production and plasmid pREP4 cotransformed into TRG8 cells to suppress basal AGT protein expression
-
transformed into Escherichia coli BL21(DE3)
-
expression in Escherichia coli
-
the gene is placed under the control of the lac promoter and overexpressed in the methyltransferase-deficient Escherichia coli strain KT233
-
expressed in Escherichia coli BL21-Codon Plus (DE3)-RIL cells
-
expressed in Escherichia coli
Q97VW7
recombinant variants are expressed in HMS174 pLyS cells
-
expressed in Escherichia coli Rosetta(DE3) cells
-
EXPRESSION
ORGANISM
UNIPROT
LITERATURE
a loss of MGMT expression is noted in 20 cases of 60 total soft tissue sarcomas
-
extensive methylation of MGMT promoter is associated with loss/reduced protein expression, methylation of MGMT promoter region is essential for methylation-induced silencing of this gene
-
interleukin-24 down-regulates O6-methylguanine-DNA methyltransferase in melanoma cells, accumulation of functional p53 is essential for interleukin-24-induced down-regulation of O6-methylguanine-DNA methyltransferase
-
neither short-term (24 h) nor long-term changes (7 weeks) in S-adenosyl-L-methionine/S-adenosylhomocysteine ratio alter global or MGMT promoter methylation, however, experimentally elevated S-adenosylhomocysteine levels significantly decrease MGMT mRNA levels by more than 50%
-
there is a good correlation between the increasing MGMT promoter methylation and decreased MGMT expression, in most patients who has been treated with temozolomide, there is decreased MGMT expression in the post treatment sample when compared to the primary sample
-
promoter methylation of O6-methylguanine-DNA-methyltransferase in lung cancer is regulated by p53
-
ependymomas lack MGMT promoter hypermethylation and show high MGMT protein expression
-
MGMT activity is significantly higher in the group with the lowest consumption of vegetables than in the group with the greatest vegetable consumption
-
resistance to alkylating agents such as temozolomide correlates with increased expression of O6-methylguanine-DNA methyltransferase
-
ENGINEERING
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
V139F
-
has an increased ability to protect against the cytotoxic and mutagenic effects of N-methyl-N'-nitro-N-nitrosoguanidine
A121E
-
no major structural change upon energy minimization, is within the DNA binding region and may therefore affect DNA binding of MGMT
A121T
-
no major structural change upon energy minimization, is within the DNA binding region and may therefore affect DNA binding of MGMT
A154T
-
ca. 4fold increased activity, AGT mutant selected using phage display
A41D/S115T/I151N
-
1.6fold increased activity, AGT mutant selected using yeast three-hybrid system
C145A
-
inactive mutant enzyme forms a specific and stable complex with a 6-O-methylguanine-containing oligonucleotide substrate
C145A
-
inactive mutant protein
C145A
-
abolishes 1,2,3,4-diepoxybutane-induced cross-linking at this site, while the formation of conjugates via neighboring Cys150 is retained
C145A
-
binds to alkylated DNA in a similar manner to wild type AGT but is unable to carry out the repair transfer, expressed in Escherichia coli, this mutant increases killing and mutagenesis by N-methyl-N'-nitro-N-nitrosoguanidine
C145F
-
appears to cause a similar change in the AGT structure as alkylation of the active site and provides a model for detailed study of the mechanism of degradation
C145S
-
inactive mutant enzyme forms a specific and stable complex with a 6-O-methylguanine-containing oligonucleotide substrate
C24A
-
mutation of Cys24 prevents the zinc-dependent alkyl transferase by N-terminal domain human AGT
C5A
-
smaller increase in stability on zinc addition than the wild-type hAGT
C5A
-
mutation of Cys5 prevents the zinc-dependent alkyl transferase by N-terminal domain human AGT
D42E/A51T/A64V/K104M
-
0.5fold increased activity, AGT mutant selected using yeast three-hybrid system
D42E/P47L/V155L/K178M
-
1.9fold increased activity, AGT mutant selected using yeast three-hybrid system
E110D/L120M
-
0.7fold increased activity, AGT mutant selected using yeast three-hybrid system
E166D
-
no major structural change upon energy minimization
E25K
-
0.7fold increased activity, AGT mutant selected using yeast three-hybrid system
E92D/I151V/R175W
-
1.0fold increased activity, AGT mutant selected using yeast three-hybrid system
F79I/V88I/F89L
-
0.7fold increased activity, AGT mutant selected using yeast three-hybrid system
G122C
-
0.9fold increased activity, AGT mutant selected using yeast three-hybrid system
G132R
-
no major structural change upon energy minimization, is within the DNA binding region and may therefore affect DNA binding of MGMT
G156A
-
40% reduced ability of the protein to react with Br(CH2)2Br
G156A
-
mutant MGMT protein that is resistant to inactivators of the wild-type protein, used in myeloprotective gene therapy
G156C
-
mutant form expressed by the medulloblastoma cell line D283 MED, mutant enzyme is not easily inhibited by O6-benzylguanine
G160R
-
28% reduced ability of the protein to react with Br(CH2)2Br
G160R
-
is as effective as wild-type in protecting cells from N-methyl-N'-nitro-N-nitrosoguanidine and N,N'-bis(2-chloroethyl)-N-nitrosourea, is strongly resistant to O6-benzylguanine
G160R
-
no major structural change upon energy minimization, is in the vicinity of the active Cys145 and may cause disturbances of O6-alkyl transfer from DNA to the protein
G160W
-
cells overexpressing W160AGT do not become labeled, even when incubated with O6-propargylguanine for extended periods of time
H29A
-
does not show the stability enehancement of wild-type hAGT with its intact zinc coordination sphere
H71Y/A154T
-
3.3fold increased activity, AGT mutant selected using phage display
H85A
-
does not show the stability enehancement of wild-type hAGT with its intact zinc coordination sphere
I143V
-
no major structural change upon energy minimization, is in the vicinity of the active Cys145 and may cause disturbances of O6-alkyl transfer from DNA to the protein, does not affect DNA repair capacity
I143V
-
no significant association between the G allele of I143Val and cancer risk is found
I143V/K178R
-
no significant effect on AGT activity, may be an increased risk for lung cancer in individuals with this change
I143V/K178R
-
enhanced green fluorescent protein-tagged MGMT variants exhibit nuclear localization patterns indistinguishable from wild type enzyme
K104E/T127A/A154T
-
4.5fold increased activity, AGT mutant selected using phage display
K107L
-
mutant is deficient in DNA repair
K107R/A154T
-
4.7fold increased activity, AGT mutant selected using phage display
K165R
-
does not abolish activity on 6-O-methylguanine but greatly reduces the ability to react with O6-benzylguanine
K165T
-
mutant form expressed by the medulloblastoma cell line D341 MED, mutant enzyme is not easily inhibited by O6-benzylguanine
K8R/K104E/I151T
-
1.4fold increased activity, AGT mutant selected using phage display
K8T/A51T/I112V/A154T
-
5.5fold increased activity, AGT mutant selected using phage display
K8T/T127A/A154T/H174R
-
5.8fold increased activity, AGT mutant selected using phage display
L33F/A68T
-
2.1fold increased activity, AGT mutant selected using yeast three-hybrid system
L33F/N123Y
-
2.2fold increased activity, AGT mutant selected using yeast three-hybrid system
L33F/V44A/V52A/A154T
-
6.1fold increased activity, AGT mutant selected using phage display
L66M/K131R
-
1.5fold increased activity, AGT mutant selected using yeast three-hybrid system
L84F
-
no major structural change upon energy minimization, may affect Zn2+ binding, does not affect DNA repair capacity
L84F
-
a significant association is found between the T allele of L84F and cancer risk
L84F
-
the L84F polymorphic variant of human O6-methylguanine-DNA methyltransferase alters stability in U87MG glioma cells but not temozolomide sensitivity, upon exposure to O6-benzylguanine, the L84F variant is degraded more rapidly than wild type
L84F/I143V/K178R
-
enhanced green fluorescent protein-tagged MGMT variants exhibit nuclear localization patterns indistinguishable from wild type enzyme, upon exposure to O6-benzylguanine, the L84F/I143V/K178R variant is degraded more rapidly than wild type
N123S
-
1.3fold increased activity, AGT mutant selected using phage display
N123V
-
no major structural change upon energy minimization, is within the DNA binding region and may therefore affect DNA binding of MGMT
N150D
-
1.8fold increased activity, AGT mutant selected using phage display
N157/S159/C62A/C150N/G131K/G132T/M134L/R135S/Q115S/Q116H/K125A/A127T/R128A/S151I/S152N
-
called MAGT with 15 different mutations in a single protein, has23fold increase in activity relative to wild-type, is resistant against N9-substituted BG derivatives used for inhibition of wild-type, shows suppressed affinity towards DNA
P140A
-
70% reduced ability of the protein to react with Br(CH2)2Br
P140K
-
95% reduced ability of the protein to react with Br(CH2)2Br as measured by loss of activity, no change in the stability of the AGT-Cys145S-(CH2)2Br intermediate
P140K
-
stable and extremely resistant to O6-benzylguanine
P140K
-
mutant MGMT protein that is resistant to inactivators of the wild-type protein, used in myeloprotective gene therapy
Q90R/K101N/F108I/V164L
-
1.2fold increased activity, AGT mutant selected using yeast three-hybrid system
R128A
-
substantially reduced AGT-mediated increase in toxicity and the induction of mutations in Escherichia coli cells treated with Br(CH2)2Br, is able to react with Br(CH2)2Br at the Cys145 acceptor site, but the resulting AGT-Cys145S-(CH2)2Br is much less able to produce a covalent adduct with DNA
R128G
-
reduces the AGT repair efficiency, no smaller effects with the O6-benzylguanine substrate than the 6-O-methylguanine
R128L
-
reduces the AGT repair efficiency, smaller effects with the O6-benzylguanine substrate than the 6-O-methylguanine
R175L
-
0.6fold increased activity, AGT mutant selected using yeast three-hybrid system
T11I/N67K/Q72L
-
1.0fold increased activity, AGT mutant selected using yeast three-hybrid system
T127A
-
2.2fold increased activity, AGT mutant selected using phage display
T38M/A41D/A64T/G173C
-
0.8fold increased activity, AGT mutant selected using yeast three-hybrid system
V149I/A154T
-
4.5fold increased activity, AGT mutant selected using phage display
V44G/V106A/I151T/A170T
-
1.4fold increased activity, AGT mutant selected using yeast three-hybrid system
V46A/A50V/P58V/A154T
-
3.4fold increased activity, AGT mutant selected using phage display
V52A/I151S/K178E
-
2.3fold increased activity, AGT mutant selected using phage display
V52I/V164M
-
2.1fold increased activity, AGT mutant selected using yeast three-hybrid system
W65C
-
no major structural change upon energy minimization, possibly unstable
Y114A
-
reduced ability of the protein to react with Br(CH2)2Br as measured by loss of activity
Y114E
-
substantially reduced AGT-mediated increase in toxicity and the induction of mutations in Escherichia coli cells treated with Br(CH2)2Br
Y114F
-
mutant form expressed by the medulloblastoma cell line Daoy, mutant enzyme is not easily inhibited by O6-benzylguanine
Y114F
-
reduces the AGT repair efficiency, smaller effects with the O6-benzylguanine substrate than the 6-O-methylguanine
Y158H
-
78% reduced ability of the protein to react with Br(CH2)2Br as measured by loss of activity, no change in the stability of the AGT-Cys145S-(CH2)2Br intermediate
E158A
-
melting temperature of mutant enzyme E83A at 5 mM urea is 90.6C, compared to 91.5C for the wild-type enzyme
E159A
-
melting temperature of mutant enzyme E83A at 5 mM urea is 91.7C, compared to 91.5C for the wild-type enzyme
E83A
-
melting temperature of mutant enzyme E83A at 5 mM urea is 89.2C, compared to 91.5C for the wild-type enzyme
E93A
-
mutant enzyme unfolds one order of magnitude faster than does the wild-type enzyme
E93A
-
stability against organic solvents does not differ from that of the wild-type enzyme
M1V/V164M
-
1.9fold increased activity, AGT mutant selected using phage display
additional information
-
deletion of more than 8 or 31 residues from the amino or carboxyl terminus, respectively, leads to the loss of both activity and substrate binding. Removal of Arg9 or Leu176 and distal residues inactivates the protein
additional information
-
three allelic variants: V1 with amino acid substitution Leu84Phe, variant V2 with amino acid substitution Trp65Cys and variant V3 with a silent mutation. Wild-type and V1 variant have similar enzymatic and physicochemical properties, while variant V2 is considered to be unstable and rare
additional information
-
the 28-amino acid carboxy-terminal tail of the enzyme is not required for activity and modulates the rate of 6-O-methylguanine DNA methyltransferase repair at reduced temperatures and plays a role in substrate specificity
additional information
-
AGT mutants resistant to inactivation by N9-cyclopentyl-O6-(4-bromothenyl)guanine
additional information
-
examination of the structural changes accompanying single nucleotide polymorphisms-related amino-acid changes in the MGMT protein
additional information
-
insertion of random amino acid loops into the protein backbone reveals mutants that react with the non-natural substrate O6-propargylguanine, libraries generated by conventional random or targeted saturation mutagenesis, by contrast, do not yield any mutants with activity towards this new substrate
additional information
-
MAGT decreased activity can be restored by combination of saturation mutagenesis of residues 150-154 and 31-35 from phage display and yeast three-hybrid system selections, reveals a mutant with 17fold higher activity than MAGT and a 52fold higher activity than wild-type AGT, is the most active AGT mutant against O6-benzylguanine derivatives described so far
additional information
-
MGMT W145 mutant does not inhibit methyl transfer by wild-type MGMT under the assay conditions used
additional information
-
mutation of Arg-128 to Ala greatly reduces the ability of AGT to repair O6-methylguanine in DNA but has no effect on the alkyl transfer reaction when the free base substrate, O6-benzylguanine is used, stability of AGT is reduced by most mutations at Lys-165
additional information
-
no differences in protein levels and catalytic activity of topoisomerase I between MGMT-proficient and MGMT-deficient cells from the Tet-On-inducible and small interfering RNA systems
additional information
-
construct human AGT-03 (where AGT sequence -V149CSSGAVGN157- is replaced with the corresponding Ogt -I143GRNGTMTG151-), exhibits enhanced DNA containing 4-O-methylthymine repair activity in vitro compared to wild type AGT
Y158H
-
stable and extremely resistant to O6-benzylguanine
additional information
Methanocaldococcus jannaschii P2
-
the H5 variant harbouring five mutations (in the helix-turn helix motif) has a catalytic activity on O-6-benzyl guanine derivated substrates, whereas its ability to bind and repair the natural DNA containing 6-O-methylguanine is completely abolished
-
additional information
-
MGMT deficiency does not result in greater mutation frequency following cyclophosphamide or 1,3-bis (2-chloroethyl)-1-nitrosourea compared with wild-type mice
P140K
-
mutant confers resistance to N,N'-bis(2-chloroethyl)-N-nitrosourea and O(6)-benzylguanine
additional information
Q97VW7
the H5 variant harbouring five mutations (in the helix-turn helix motif) has a catalytic activity on O-6-benzyl guanine derivated substrates, whereas its ability to bind and repair the natural DNA containing 6-O-methylguanine is completely abolished
Renatured/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
renaturation by dilution with buffer from 8 M urea or 6 M guanidine HCl instantly restores the secondary structure of the Ada protein to a state that is almost indistinguishable from the native state. Kinetics of renaturation is fast, at 0C the restoration is quantitative in less than 30 s. The heat-coagulated protein can be restored to full activity by cycling it through treatment with 8 M urea or 6 M guanidine
-
APPLICATION
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
medicine
-
transgenic rats expressing Ada-C are resistant to mammary tumor induction by N-methyl-N-nitrosourea but not by N-ethyl-N-nitrosourea
analysis
-
ability to specifically label AGT fusion proteins in the presence of endogenous AGT, after brief incubation of the cells with a small-molecule inhibitor, may significantly broaden the scope of application of AGT fusion proteins for studying protein function in living cells
analysis
-
N-terminal domain plays a critical structural role in maintaining an active configuration of the C-terminal domain, N-hAGT and C-hAGT domains can protect from N-methyl-N'-nitro-N-nitrosoguanidine in Escherichia coli GWR-109 cells
analysis
-
overexpression of human MGMT provides protection against the toxic effects of N-methyl-N'-nitro-N-nitrosoguanidine
analysis
-
strategy of loop insertion to alter enzyme specificity shall be general and applicable to other classes of proteins, the isolated AGT mutant can be applied in molecular imaging, where the mutant and parental AGTs are used to label two different AGT fusion proteins with different fluorophores in the same living cell or in vitro, allows establishment of fluorescence-based assays to detect protein-protein interactions and measure enzymatic activities
diagnostics
-
introduction of the MS-MLPA assay may not only be helpful for predicting response of gliomas to temozolomide, but may also facilitate tailor-made treatment with other chemotherapeutic agents for a variety of tumors
drug development
-
highly effective inactivation of MGMT by an oligodeoxyribonucleotide containing O6-(4-bromothenyl)guanine suggests that such oligodeoxyribonucleotides might have therapeutic applications if problems of delivery can be addressed
medicine
-
the enzyme is important in cellular resistance to certain alkylating antitumor agents such as the methylating drug temozolomide. Cisplatin is able to decrease enzyme levels in Jurkat cells, probably via the inhibition of gene transcription. The clinical efficiacy of triazene compounds might be improved by combination with cisplatin using appropriate doses and schedules of administration
medicine
-
high level of enzyme in tumors and relative resistance to cyclophosphamide in lung cancer indicates that 6-O-methylguanine-DNA methyltransferase may be a predictive factor of resistance to cyclophosphamide
medicine
-
the efficiacy of 6-O-benzylguanine as a chemomodulator depends on the extent of depletion of 6-O-methylguanine DNA methyltransferase in normal tissues and the optimal therapeutic index for combination of 6-O-benzylguanine and 1,3-bis(2-chloroethyl)-1-nitrosourea therapy should be achieved by depleting 6-O-methylguanine DNA methyltransferase in the target tumor for 24 h with minimal depletion in normal tissues
medicine
-
clonal selection of AGT mutants during trteatment with O6-benzylguanine plus an alkylator may produce resistance to this intervention in clinical settings
medicine
-
DNA hypermethylation and silencing of MGMT are frequent and rather early events in esophageal squamous cell carcinogenesis. Hypermethylation and inactivation of MGMT may be prevented or reversed by dietary polyphenols, (-)-epigallocatechin-3-gallate and genistein, for the prevention of carcinogenesis
medicine
-
O4-benzylfolic acid is 30times more active than O6-benzylguanine against the wild-type alkyltransferase, inactivation of P140K mutant alkyltransferase. Inhibitor shows promise as an agent for possible tumor-selective alkyltransferase inactivation superior toO6-benzylguanine as a chemotherapy adjuvant
medicine
-
AGT-DNA cross-linking is a likely mechanism of 1,2,3,4-diepoxybutane-mediated cytotoxicity in cells expressing this important repair protein
medicine
-
alkyltransferase activity in tumors protects them from therapeutic agents such as temozolomide and N,N'-bis(2-chloroethyl)-N-nitrosourea, polymorphisms in the AGT gene
medicine
-
cigarette smoking not only induces O6-alkylguanine lesions, it inhibits the repair of these adducts by MGMT, O6-alkylguanine adducts are well established carcinogenic lesions and decreased repair of such lesions may increase susceptibility to lung cancer in smokers
medicine
-
combining cisplatin and temozolomide is based on the potential for improved antitumour activity, combination is well tolerated in children and adolescents, generating no toxicity greater than that of the single agents
medicine
-
even slight alterations in the active site pocket of AGT do not prevent its ability to protect cells from alkylating agents, can block the paradoxical enhancement of the genotoxicity of the larger alpha,omega-dihaloalkanes by reducing the reaction with Cys145
medicine
-
highly significant correlation between AGT protein expression assessed by immunohistochemistry and AGT activity assessed by HPLC, marginal statistically significant correlation between immunohistochemistry and real-time methylation-specific PCR, and no significant correlation between AGT protein activity assessed by HPLC versus real-time methylation-specific PCR. Cross-tabulation of immunohistochemistry and real-time methylation-specific PCR data based on prognostic groups shows no significant relationship, suggesting that one assay cannot be used interchangeably for another, thus the results cannot be used to guide glioma therapy decisions
medicine
-
inhibition of tumor suppressor p53 by RNAi is accompanied by down-regulation of MGMT gene expression, but is not associated with a discernible change in the pattern of MGMT promoter methylation
medicine
-
MGMT can modulate cytotoxicity of camptothecin-derived topoisomerase I inhibitors, MGMT overexpression reveals more resistance to 1,3-bis(2-chloroethyl)-1-nitrosourea, camptothecin, 7-ethyl-10-hydrocamptothecin and topotecan, alteration of MGMT expression coincides with camptothecin-induced cell death and poly(ADP-ribose) polymerase cleavage
medicine
-
temozolomide appears to be a good candidate for use in conjunction with hyperthermia for regional chemotherapy of melanoma
medicine
-
inhibition of tumour MGMT by pseudosubstrates to overcome tumour resistance is under clinical evaluation, MGMT overexpression in haematopoietic stems cells has been shown to protect normal cells against the myelosuppressive effects of chemotherapy
medicine
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MGMT can confer resistance to the cancer chemotherapeutic effects of the class of DNA damaging drugs, inactivation of MGMT is thus a practical approach to improving the efficacy of such agents
medicine
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determination of MGMT in peripheral blood mononuclear cells can identify patients at greatest risk of toxicity with O6-alkylating agent chemotherapy or who are suitable for dose intensification, MGMT protects against the toxic effects of O6-alkylating agents
medicine
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MGMT is a factor of chemoresistance to alkylating drugs in anaplastic ependymomas
medicine
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the combination of high thymidylate synthase and low O6-methylguanine-DNA methyltransferase expression is a significant predictor of a poor response to fluoropyrimidine treatment
medicine
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the enzyme protein expression is an unfavorable prognostic factor for patients with gliosarcoma
molecular biology
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modest binding cooperativity and high binding densities of AGT are adaptations that allow the enzyme to efficiently search for lesions in the context of chromatin remodeling and DNA replication
medicine
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expression of additional AGT in a variety of tissues in transgenic mice protects against carcinogenesis
medicine
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MGMT significantly protects against in vivo temozolomide-induced mutations
medicine
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tumor suppressor p53 positively regulates MGMT gene expression in murine astrocytes
medicine
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the results suggest that expression of MGMT could enhance the capacity of bone marrow-derived cells to repopulate lung epithelium, and when used in combination with a gene of interest, MGMT could have therapeutic applications